1. Field of the Invention
The present invention relates to a prefabricated pre-cast culvert provided with couplings.
2. Description of the Prior Art
As well known, pre-cast culverts, which are made of reinforced concrete, are buried under roads so that they are used for sewer pipes, waterways, cavity passages, underground distribution lines, communication cable lines, and other passages. Such pre-cast culverts are used in the form of a variety of prefabricated modular products in order to reduce labor costs and construction time or to avoid traffic jams at places where culverts are buried.
In such conventional prefabricated pre-cast culverts, adjacent ones are connected to each other using a water-resistant material and a back-up material provided at their connections. However, a degradation may occur in the water-resistant material provided at those connections. Furthermore, there may be a differential subsidence of the ground, on which culverts are placed, due to an insufficient hardness of the ground. For these reasons, the connected culverts may have discontinuous portions resulting in a leakage of water. This results in a problem in quality control.